Rotary core drill



Y Novi-9,1938 l J. H, HOWARD 21,133,006

` ROTARY GORE-DRILL Fied oet. 14, 1955 L l I. QN

/lv l Patented Nov. 2.9, 1.938.

UNITED sTATEs PATENT OFFICE ROTARY CORE DRILL John H. Howard, Huntingtonv Park, Calif.

Application October 14, 1935, Serial No. 44,884

3 Claims. (CL 255'12) This invention relates to a well tool and relates more particularly to a well drill capable of obtaining a sample or core of the earth formation. A general object of this invention is to provide 5 a simple, practical and improved rotary core taking Well drill.

Another object of this invention is to provide a rotary well drill embodying a core barrel having a cutting head and adapted to be fed into the earth formation to cut and receive a core of the formation'and then be withdrawn from the well to permit the core to be examined Without removing the outer barrel or drill proper.

Another object of this invention is to provide a Well drill of the character mentioned in which the core barrel may be fed into the earth formation in advance of the head of the drill and rotated with the drill to obtain a core of the Aformation and then removed from the well with the core contained therein without enlarging the bore it has formed, thus leaving a reduced bore or rat-hole. The operation of the core barrelin advance of the drill head to form a reduced .bore and the subsequent removal of the core barrel without enlarging the reduced bore are important and facilitate the testing of the Well as a suitable well tester may be run into the rathole or reduced bore following the examination of the core obtained without the necessity of running a special drill into the well to form a rat-hole to receive the tester.

Another object of this invention is to provide a sample taking drill of the character mentioned in which the core barrel is fed downwardly into the formation in advance of the outer barrel by hydraulic pressure or iiuid pressure.

Another object of this invention is to provide a well drill of the character mentioned that embodies a simple positive and eiective means for transmitting rotation from the outer barrel to the uid pressure actuated core barrel during the drilling and core cutting operation.

Another object of this invention is to provide a drill of the character mentioned that includes means for informing the driller that the core barrel has reached the lower end of its downward stroke and, therefore, has received a core of sufficient length.

A further object of this invention is to provide a core taking well drill of the character mentioned that embodies a minimum number of simple sturdy parts and that is inexpensive of manufacture.

The various objects and features of my invention will bel fully understood from the following detailed description of a typical preferred form and application of my invention, throughout. which description reference is made to the accompanying drawing, in which: K 5

Fig. 1 is a central longitudinal detailed sec" tional view of the drill provided by this invention illustrating the core barrel in the operative position. Figs. 2, 3 and 4 are transverse detailed sectional views taken as indicated by lines 2 2, 10 3 3 and 4-4, respectively on Fig. 1.

The well drill of the present invention includes, generally, an outer barrel I0 having a cutting head Il on its lower end, a core barrel I2 adapted to be run into the outer barrel I0, 15 and means I3 for feeding or advancing the core barrel I2 into the earth formation to obtain a core. f

The outer barrel I0 constitutes the body of the drill and is a tubular structure adapted to be 20 y connected with the lower end of a drilling string. In the particular form of the invention illustrated in the drawing the outer barrel I0 is sectional comprising an upper tubular section I4 and a lower tubular section I5. Means isprovided at 25'l the upper end of the upper section I4 for facilitating the connection of the drill withV the drilling string. This means may take the form of a threaded socket I6 for receiving a threaded pin on the lower end of the string. A suitable 30 threaded pin and socket connection I1 is provided to connect the two sections I4 and I5 of the barrel I0. A threaded pin I8 is provided on the lower end of the section I5 to carry the cutting head II. In accordance with the invention any 35 suitable form or type of cutting head may be provided on the barrel I0. In the drawing there is shown a typical cutting head comprising a tubular shoe I9 threaded on the pin I8 and spaced cutting parts 20 on the shoe. The cut- 40 ting parts 20 are in the form of lblades projecting downwardly and outwardly from the lower end of the.shoe I9 for making an annular cut in the earth formation. The blades v2li project inwardly at the lower end of the shoe I9 and are 45 operable to make an annular cut of substantial radial width or extent. During the drilling operation circulation fluid `passes downwardly through the longitudinal opening 2l of. the barrel I IJ to discharge from the cutting head II. 50 The opening 2l is comparatively large in diameter to receive the core barrel I2 and parts are provided on its wall to cooperate with the core barrel as will be hereinafter described.

'I'he core barrel I2 is an elongate tubular mem- 55 ber adapted to be dropped or lowered through the drilling lstringlto pass into the outer barrel IIJan'd may be' fed downwardly by the means I3 to cut into the formation in advance of the cutting head II and receive a core. The core barrel I2 is comparatively long and is adapted to t in the opening 2| of the outer barrel III with substantial clearance leaving a uid passage P. The longitudinal opening 22 of the barrel I2 is open at its lower end and is adapted to receive the core of the earth formation as the barrel is rotated and fed downwardly into the earth formation. In accordance with the invention a cutting head 23-is provided on the lower end of the core barrel I2. The cutting head 23 is proportioned to pass downwardly through the outer barrel III and to pass between the blades 20 of,

cutting head 23 includes cutting parts 24'in the Vwardly seating valve or ball 3I.

form of downwardly projecting blades arranged in an annular series to make an annular cut when the barrel I2 is rotated and fed downwardly. A core catcher 25 is provided to retain and support the core in the core barrel I2. The particular core catcher 25 illustrated in the drawing is amore or less typical form of core catcher rotatably supported in the cutting head 23 and embodying upwardly and inwardly projecting spring ngers 26.

A valve is provided on the upper end of the core barrel I 2 to prevent the circulation fluid from washing downwardly through the core barrel and to permit the discharge of fluid from the core barrel as it is displaced by the entering core. Ihe vvalve may include a connector or adapter 21 threaded into a socket 28 in` the upper end of the. core barrel I2 and carrying a transverse or horizontal web 29. The web 29 has a, central vertical port 38 which is controlled by a down- An upstanding rim 32 is provided on the web 23 around the port 30 to wassist in retaining the ball 3| against displacement. A member 33 projects upwardly from the adapter 21 and has a Valve chamber 34 receiving the n'm 32 and confining the movable ball 3|. Ports 35 connect the chamber 34 with the passage P to permit the discharge of fluid from the interior of the core barrel I2 when th valve or ball 3| is open.

'Ihe invention provides a novel releasable drive for transmitting rotation from the outer barrel I0 to the core barrel I2.` This drive is such that it is automatically engaged when the core barrel I2 is dropped or run into the outer barrel I0. 'Ihe rotation transmitting drive includes a plurality of spaced longitudinal splines 36 on the wall of the openings 2| and a plurality of spaced longitudinal splines 31 on the core barrel I2 for cooperating with the splines 36. The splines 36 are preferably on the interior of the lower barrel section I5. When in engagement the splines 36 and 31 form a positive rotative drive between the outer barrel IIIV and the core barrel I2.

Novel and particularly effective means is provided for guiding or directingthe splines 31 of the core barrel I2 between the splines 36 when the core barrel is dropped or run into the outer barrel I II. A plurality of circumferentially spaced lugs 38 is provided on the wall of the opening 2|. The lugs 38 are spaced above the upper ends ofthe splines 36 and are in vertical or longitudinal alignment with the splines. The upper ends of the lugs 38 are pitched or inclined upwardly and inwardly to central upwardly facing edges. The lower ends of the splines 31 may be similarly formed and when the core barrel I2 is lowered or run into the outer barrel III the lower ends of the splines 31 engage the pitched ends of the lugs 38 and this cooperation causes the core barrel I2 to turn to a position whereits splines 31 are free to pass downwardly between the splines 36. The splines 31 are thus engaged with the splines 36 without excessive shock to the parts. The splines 36 and 31 are formed and related to centralize the core barrel I2 in the outer barrel I0 `and to permit the free downward feeding or movement of the core barrel I2 relative to the outer barrel II). The spaces between the spaced splines 31 constitute continuations of the passage l?, as illustrated in Fig. 4, when the core barrel I2 is in the operative position within the outer barrel I0. The lugs 38 spaced upwardly from the splines 36 may assist in guiding and centering the core barrel I2.

The means I3 for advancing or feeding the core barrel I2 into the earth formation isla feature of the invention as it provides for the advancement of the core barrel I2 relative to the outer barrel I0 during rotation of the drill to movevthe cutting head 23 downwardly in advance of the cutting head II so that the barrel I2 receives a .core of the formation in advance of the cutting head II. The feeding or advancing means `I3 is in the nature of an hydraulic means or iiuid pressure means and is under the full control of the driller. In accordance with the invention the means I3 includes a piston or plunger on the upper end of the core barrel I2 operating in the opening 2| of the barrel Il).l 'Ihe plunger comprises a sealing element 40 surrounding the upper end portion of the member 33 and bearing downwardly against an annular flange 4I on the member. A head or nut 42 is threaded on the upper end portion of the member 33 to clamp or retain the sealing element 40 in position. 'I'he sealing element 40 is shaped and proportioned to effectively seal outwardly against the wall of the opening 2| under the action of downward uid pressure.

Means is provided for producing a diierential or drop in pressure at the opposite sides of the sealing element 40 so that the pressure on the circulation fluid pumped through the drilling string feeds or forces the core barrel I2 down-.- wardly. The member 33 has la fluid chamber 43 below the flange 4I and spaced ports 44 extending upwardlyfrom the chamber 43 to its upper end. Ports 45 in the wall of the member 33 connect the chamber 43 with the fluid passage P. Orice members or chokes 46 having small ports or passages 41 are provided in the upper portions of the ports 44. The chokes 46 operate to materially restrict the flow downwardly through the ports 44 to provide for a substantial drop in fluid pressure at the lower side of the sealing element 40 so that the circulation iiuid under pressure pumped downwardly through the string acts on the sealing element 40, the nut 42 and the upper end of the member 33 to force or feed the core barrel I2 downwardly relative to the outer barrel I0. A stem 48 is provided on the upper end of the member 33 to facilitate the handling of the core barrel I2 by a line provided with an overshot or other device for engaging the stem. The upwardly projecting stem 48 is provided with a tapered head 49 readily engageable by an overshot or similar ilshing tool.

In accordance with the invention the drill is constructed to automatically signal to the driller that the core barrel I2 has recelveda sufficient amount of core. During the core receiving operation the fluid pressure acting on the sealing element 40, the nut 42 and the upper end of the member 33 feeds the core barrel I2 downwardly more rapidly than the outer barrel I is advanced, moving the head 23 downwardly into the earth formation in advance of the head II. The lower side of the flange 4I is adapted to cooperate with the upper ends of the lugs 38 to limit the downward travel of the core barrel I2 relative to the outer barrel I0. The parts are proportioned and related so that the inner sides of the lugs 38 directly oppose and close or substantially close the ports 45 when the lower side of the flange 4I cooperates with the upper sides of the lugs 38.` Thus the downward flow of the circulation fluid is stopped or materially retarded simultaneously with the stopping of downward movement of the core barrel I2 relative to the outer barrel I0. The restriction or closing of the ports 45 by the lugs 38 causes the pump or pumps delivering the circulation fluid to the drilling string to labor, indicating to or informing the drillerv that the core barrel I2 has reached the lower end of its downward stroke and has received a sufficient core.

In operation the cuter barrel Ill is connected with the lower end of a well drilling string and run into the well for operation in accordance with the rotary method of well drilling. When it is desired to obtain a sample or core of the earth formation to determine its character the core barrel I2 is dropped or run through the drilling string on a cable to land or come to rest in the outer barrel I0. As the core barrel I2 moves downwardly through the outer barrel I0 the lower ends of the splines 31 contact or engage the tapered upper ends of the lugs 38. The taper of the lugs 38 causes the core barrel I2 to turn to a rotative position where its splines 31 may pass down between the splines 36 on the wall of the opening 2|. Thus the splines 36 and 3I are engaged to form a positiverotative drive between the outer barrel III and the core barrel I2.

Rotation of the drilling string is then resumed and the circulation uid is pumped downwardly through the drilling string to pass through the chokes 46, the ports 44, the chamber 43, the ports 45 and ow out through the passage P. The chokes 4'I provide for a substantial drop in the pressure on the fluid below the sealing element 48 so that the pressure acting on the sealing element, the nut 42 and the upper end of the member 33 urges or feeds the core barrel I2 downwardly. Thus the core barrel I2 is fed downwardly relative to the outer barrel I 0 and is rotated with the outer barrel so that its cutting head 23 cuts into the earth formation. The hydraulic pressure acting downwardly on the core barrel I2 causes the cutting head 23 to drill into the formation in advance of the cutting head Il. The cutting head 23 fed downwardly in advance of the cutting head II forms a reduced bore in the lower end of the well and leaves a core which is received in the core barrel I2. As the core is receivedin the core barrel I2 the fluid trapped in the core barrel is displaced through the port 30, the chamber 34 and the ports 35.

The drilling or coring operation is continued until the core barrel l2 is fed downwardly relative to the outer barrel I0 to a point wherev the lower end ofthe flange 4I contacts the lugs 38 This contact of course limits downward movement of the core barrel I2. When the flange 4I is in engagement with the lugs 38 the lugs cppose the ports 45 to close or restrict the ports. This stops or reduces the downward flow through the drilling string and causes the pumps forcing the fluid through the string to labor. The laboring of the pump or pumps indicates to the driller that the core barrel I2 has reached the lower end of its stroke and has obtained a core of sufficient length. When the pump or pumps labor the driller discontinues the rotation and downward feed of the drilling string and prepares to remove the core barrel I2. A cable carrying an overshot or the like is run into the drilling string and the overshot or fishing tool is engaged with the stem 48 to remove the core barrel. The line or cable is raised to pull the core barrel I2 `upwardly out of the outer barrel IIJ and upwardly through the drilling string. When the core barrel I2 is movedv upwardly the core catcher 25 grips and holds the core to retain it in the core barrel. Thus the core is retained in the core barrel I2 and maybe examined when the core barrel has been brought to the surface of the ground.

The withdrawal of the core barrel I2 as just described leaves a reduced bore or rat-hole in the lower end of the well. If the sample or core obtained in the core barrel indicates that it is desirable to make a test of the formation a well tester may be run into the well to pass or extend into the reduced bore formed by the cutting head 23 of the core barrel I2. The drill involving the core barrel I2 fed into the formation in advance of the principal cutter II and removable from the well without enlarging the reduced bore it has formed conditions the well for testing by a well tester without further drilling. If the charm acter of the core obtained is such that it is not deemed advisable to test the formation the drilling may be continued with the drill and cores may be taken from time tov time by means of the core barrel I2. The present invention provides a rotary well drill involving a core taking means that is positively rotated with the drill and that is fed into the formation in advance of the principal cutter by hydraulic pressure to obtain a core and to leave a reduced bore or rathole. The tool is easy to control and operate and involves a minimum number of sturdy parts.

Having described only a typical preferred form` and application of my invention I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A rotary well drill including a tubular body adapted to be operated on a tubular drilling string, a tubular cutting head on the lower end of the body, a core barrel adapted to be passed through the string to the interior of the body, means for transmitting rotation from the body to the core barrel, a cutter on the core barrel operable to-cut a core for reception by the core barrel, means for feeding the core barrel downwardly to cause its cutter to'cut a core in ad- Vance of the cutting head, and means for audibly signaling to the driller when the core barrel has been advanced a predetermined extent.

2. In a rotary well drill construction, a barrel adapted to be operated on the lower end of -a tubular drilling string, longitudinal splines on theinterior of the barrel, a core receiving barrel adapted to be passed through the string into the barrel, splines on the core receiving barrel adapted to slidably cooperate with the splines on the barrel, lugs on the barrel for guiding the splines of the core barrel between the splines of the barrel, and a plunger carried by the core barrel for operating in the barrel, a head on the core barrel end of the barrel, a, core barrel adapted to be passed through the string into the barrel, parts on thewbarrel and core barrel adapted to cooperate to transmit rotation and allow longitudinal movement of the "core barrel in the barrel, there being a longitudinal uid passage between the barrel and core barrel, a plunger on the core barrel operable in the barrel, there being a port in the core barrel establishing communication.

between the string and the passage and eiecting a drop in pressure below the plunger whereby fluid pumped through the string feeds the core barrel downwardly relative to the barrel, and a part on the barrel adapted to restrict the ilow through the port when the core barrel has been fed downwardly a predetermined extent.

JOHN H. HOWARD. 

